Field of the Disclosure
The present disclosure relates in general to a spectrally encoded endoscope (SEE), and more particularly, to an SEE with radial-line scanning on a two-dimensional (2D) sensor.
Description of the Related Art
Spectrally encoded endoscopy (SEE) is capable of making high resolution, real time imaging in ultra-miniature probes with diameter smaller than 1 mm. SEE uses a broad-bandwidth light source, miniature focusing optics and a diffraction grating to simultaneously focus multiple points along a traverse line within the sample and detect the reflectivity from the sample.
The SEE probe illuminates the sample with an array of focus spots, while each position, that is, each dispersion direction, is encoded with a different wavelength. Following transmission back through the optical fiber, the reflectance as a function of traverse location is determined by measured by scatter and reflected spectrum. The other dimension of the image is obtained by mechanically scanning the SEE probe at a slow rate, typically around 24 to 60 Hz. Light reflected from the sample can be detected with an imaging spectrometer with a high-speed line-scan sensor. When the line-scan sensor is used in a spectrometer, the spatial information in the scanning direction, that is, the direction perpendicular to the dispersion direction, is resolved by the fast read-out of the line sensor.
In general, the dispersed spectrum from a SEE probe is not uniformly scanning on the sample when the SEE probe rotates. That is, the sample is not equally sampled by the dispersed spectrum. However, as the detected spectrum from the sample is equally sampled on the sensor of the spectrometer, an under sampling issue could arise when the sampling theory fails at certain wavelength regions on the spectrometer.